Title :
Adaptive encoding of fixed codebook in CELP coders
Author_Institution :
Human & Comput. Interaction Lab., Samsung Adv. Inst. of Technol., Kyungki, South Korea
Abstract :
We propose an adaptive encoding method of fixed codebook in CELP coders and implement an adaptive fixed code excited linear prediction (AF-CELP) speech coder. The AF-CELP exploits the fact that the fixed codebook contribution to the speech signal is also periodic as the adaptive codebook (or pitch filter) contribution. By modeling the fixed codebook with the pitch lag and the gain from the adaptive codebook, the AF-CELP can be implemented at low bit rates as well as low complexity. Listening tests show that a 6.4 kbit/s AF-CELP has a comparable quality to the 8 kbit/s CS-ACELP
Keywords :
adaptive codes; linear predictive coding; speech coding; speech intelligibility; vocoders; 6.4 kbit/s; 8 kbit/s; AF-CELP; CELP coders; adaptive codebook; adaptive encoding; adaptive fixed code excited linear prediction; fixed codebook; listening tests; low bit rates; low complexity; pitch filter; pitch lag; speech quality; speech signal; Adaptive filters; Bit rate; Decoding; Encoding; Humans; Information processing; Quantization; Shape; Speech coding; Testing;
Conference_Titel :
Acoustics, Speech and Signal Processing, 1998. Proceedings of the 1998 IEEE International Conference on
Conference_Location :
Seattle, WA
Print_ISBN :
0-7803-4428-6
DOI :
10.1109/ICASSP.1998.674389
